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Friday, September 23, 2011

The neutrino's saga continues

Physicists wary of junking light speed limit yet
(AP) -- Physicists on the team that measured particles traveling faster than light said Friday they were as surprised as their skeptics about the results, which appear to violate the laws of nature as we know them.

"Going faster than light is something that is just not supposed to happen, according to Einstein's 1905 special theory of relativity. The speed of light - 186,282 miles per second (299,792 kilometers per second) - has long been considered a cosmic speed limit.
The team [...] fired aneutrino beam 454 miles (730 kilometers) underground from Geneva to Italy.
They found it traveled 60 nanoseconds faster than light."

The OPERA neutrino experiment at the underground Gran Sasso Laboratory has measured the velocity of neutrinos from the CERN CNGS beam over a baseline of about 730 km with much higher accuracy than previous studies conducted with accelerator neutrinos. The measurement is based on high-statistics data taken by OPERA in the years 2009, 2010 and 2011. Dedicated upgrades of the CNGS timing system and of the OPERA detector, as well as a high precision geodesy campaign for the measurement of the neutrino baseline, allowed reaching comparable systematic and statistical accuracies. An early arrival time of CNGS muon neutrinos with respect to the one computed assuming the speed of light in vacuum of (60.7 \pm 6.9 (stat.) \pm 7.4 (sys.)) ns was measured. This anomaly corresponds to a relative difference of the muon neutrino velocity with respect to the speed of light (v-c)/c = (2.48 \pm 0.28 (stat.) \pm 0.30 (sys.)) \times 10-5.